To find the surface area of a rectangular prism (like a textbook), you can use the formula:
\[ \text{Surface Area} = 2(lw + lh + wh) \]
where \( l \) is the length, \( w \) is the width, and \( h \) is the height.
Given the dimensions of the textbook:
- Length (l) = 14 in.
- Width (w) = 2 in.
- Height (h) = 9 in.
Now, we can calculate each of the areas:
- \( lw = 14 \times 2 = 28 \)
- \( lh = 14 \times 9 = 126 \)
- \( wh = 2 \times 9 = 18 \)
Now, substitute these values into the surface area formula:
\[ \text{Surface Area} = 2(28 + 126 + 18) \]
Now calculate the sum inside the parentheses:
\[ 28 + 126 + 18 = 172 \]
Now, multiply by 2:
\[ \text{Surface Area} = 2 \times 172 = 344 \]
Therefore, the surface area of the textbook is 344 in².
The correct response is:
344 in.²